Arrangement of an electromagnetic pump immersed in a liquid material providing a constant discharge

ABSTRACT

Two sets of connecting rods pivotably connected at one end on each side of a pump and at their other ends to a vertical arm fixed to the ladle control vertical stability of the pump and its depth of immersion through counterweights adjustably fixed to the outer end of an extended rod by forming an articulated parallelogram.

United States Patent 11 1 1111 3,864,061

Carbonnel et al. Feb. 4, 1975 ARRANGEMENT OF AN ELECTROMAGNETIC PUMP IMMERSED IN [56] References Cited A LIQUID MATERIAL PROVIDING A UNITED STATES PATENTS CONSTAN SC RG 2,190,968 2/1940 Acree et al. 417/61 2,755,327 7/1956 Tama 417/50 [75] Inventors gfg gg x if gfig Monaud 3,453,460 7 1969 Butler et a1. 417/50 [73] Assignee: Groupement Atomique Alsacienne Primary ExaminerWilliam L. Freeh Atlantique, Le Plessis Robinson, Attorney, Agent, or FirmSughrue, Rothwell, Mion, France Zinn & Macpeak [22] Filed: Sept. 28, 1973 [57] ABSTRACT [21] Appl- No: 401,789 Two sets of connecting rods pivotably connected at one end on each side of a pump and at their other 30 Foreign li i p i i Data ends to a vertical arm fixed to the ladle control vertical stability of the pump and its depth of immersion Sept. 28, 1972 France 72.34393 through counterweights adjustably fixed to the Outer [52] US. Cl. 417/50 and of an extended rod y forming an articulated 51 1111. c1. H02k 45/00 anemgram- [58] Field of Search 417/50, 360, 61, 902 4 Claims, 1 Drawing Figure Q1 [III] A ARRANGEMENT OF AN ELECTROMAGNETIC PUMP IMMERSED IN A LIQUID MATERIAL PROVIDING A CONSTANT DISCHARGE BACKGROUND OF THE INVENTION 1. Field of the Invention:

The present invention relates to the arrangement of an electromagnetic pump immersed in a liquid metal ladle or in a crucible, providing a constant discharge independent from the present level of metal in the said ladle or in the said crucible.

2. Description of the Prior Art:

Various electromagnetic pumps for liquid metals either of the induction type or of the conduction type, arranged as fixed units above a ladle or a circuit containing a liquid metal and enabling predetermined quantity of liquid metal intended, for example, for filling a metal mould, are known. In that case as in other like cases, the quantity of liquid metal discharged must be strictly constant. As the receptable containing-the liquid metal is emptied, the height to which the liquid metal must be pumped increases. Now, it is known that at a given lifting height H of the liquid metal, there corresponds, for agiven service voltage U, a discharge value Q. The result of this is thatif the discharge Q of the pump is to be kept constant, it is necessary to increase the voltage U applied to the pump when the level of the metal lowers in the pump and that consequently, the lifting height increases, it is evidentlypossible to obtain the same result by increasing the duration of the pumping to compensate for the decrease in the discharge. In both cases alike, it is necessary to have available on the one hand, a device for measuring the level of the metal whose accuracy may be rendered defective when the liquid metal is particularly corrosive and on the other hand, a regulating device controllingthe voltage applied to the pump or the pumping time.

Various inventors have recommended a more simple solution which consists in making the pump float-on the surface of the liquid metal and in compensation of the excess weight of the pump on the Archimedean thrust by a counter-weight. Such a method is valid only in the case where the centre of gravity of the pump is situated fairly low, that is, in the case where the windings are at the level and, more especially, below the level of the liquid metal, this being possible only when the pumped metal remains liquid at moderate temperatures, so that this way of proceeding can be used only in the pumping of sodium or of metals having a low melting point.

In the case of corrosive metals having a high melting point, such as aluminium or cast iron, the methods described above are found to be defective. Indeed, in that case, when the pump is produced so that the windings giving rise to the magnetic field are installed on the top part of the pump body and the centre of gravity of the pump is placed much higher than in a pump of a more conventional type, it is then no longer possible to fix the pump to a counter-weight by means ofa cable passing through a pulley, for the pump would have a tendency to tilt in the liquid metal, more particularly under the effect of the thrust of the metal at each starting up operation. In the case of a conduction pump containing a liquid metal spire, the latter then ceases to be completely filled and a risk of unpriming of the pump therefore appears. Lastly, in numerous cases, the lower part of the pump is made of a substance which, when hot, withstands the very corrosive action of the metal but not necessarily the action of air. An extra risk which should be avoided then appears.

It therefore seemed to the Applicant that it was desirable to produce an arrangement enabling the thorough immersing of a pump in a liquid metal, enabling the said pump to be held in a constantly vertical position whatever the level of the liquid metal in the ladle or the crucible from which it draws the liquid metal may be and keeping, moreover, a constant discharge height.

SUMMARY OF THE INVENTION The object of the invention is therefore the arranging of an electromagnetic pump immersed in a ladle of liquid metal, providing a discharge independent from the variations in the level of the bath, characterised in that it comprises means keeping the depth of immersion of the said pump constant and simultaneously keeping the pump in the vertical position.

Under the action of the electromagnetic pump, the liquid metal flux rises along an inclined tube, ending in a casting nozzle. A spout enabling the conveying of the liquid metal to its destination: mould or crucible, according to the problem dealt with-is arranged, in general, below the casting nozzle.

When the pump is in service, the level of the liquid metal may vary in appreciable proportions in the ladle fromwhich it is drawn. The displacement of the pump brings about the displacement of the casting nozzle. It is therefore necessary to relate the displacement of the spout with the displacement of the casting nozzle. It is nevertheless desirable for the lower end of the spout to keep a substantially fixed position which will be designated herebelow by the expression filling point;" this will be, for example, the input of the mould to be fed. The result of this is that the mechanical connections imposed on the pump affect, in their turn, the connection to be established between the casting nozzle of the tube and the upper end of the spout. In this way, it is possible to obtain a perfectly satisfactory arrangement of the pump only if the connection of the pump with the ladle which supports it and the connection of the casting nozzle with the spout are adpated to each other and form a combination together.

These considerations have guided the inventor when producing an arrangement for an immersed pump.

The object of the invention is also the arrangement of a partly immersed pump in a liquid metal ladle providing a discharge independent from the variations in the level of the bath comprising means keeping the depth of immersion of the said pump constant, characterised in that means acting in combination with the preceding means ensure a substantially fixed position at the base of the liquid metal discharge spout regardless of variation in the level of the bath.

The invention is also characterised in that the means keeping the depth of immersion of the pump constant whatever the variation is the level of the bath may be are constituted by two sets of two connecting rods having the same length, forming a double articulated parallelogram, two apexes of each of the parallelograms being fixed to a generating line of the cylindrical pump body by trunnions, whereas other two apexes are fixed to a vertical arm connected to the ladle.

In each parallelogram, the lower arm is extended towards the outside of the pump and forms a support for various elements forming a counter-weight.

The action of that counter-weight is composed with the Archimedean thrust to keep the level of immersion of the pump constant once the depth of immersion has been adjusted by the position of the counter-weight and to ensure, hence, a strictly constant lifting height of the metal if the voltage applied to the terminals of the pump remains constant.

The upper connecting rods placed on either side of the pump body offer resistance to the torque which is produced each time the pump is started up and which tends to make the latter tilt.

The result of this is that the pump remains vertical during all its displacements and that the elements of the pump placed below the line of immersion remain in the liquid metal. They are protected from any untimely action of the oxygen in the air. The result of this is also that when the pump put into service is a conduction pump, the liquid metal spire remains permanently filled, thus eliminating all danger of unpriming. The same advantage is observed in the induction pump where a part of the winding remains permanently below the line of immersion.

Lastly, subsequent to the connection of the, pump with a fixed vertical arm, connected to the wall of the ladle through a double parallelogram, it will be conceived that avariation in the level in the ladle tending to fill it contributes to making the pump rise, moving it away from the said vertical arm. Moreever, when the ladle is full, the casting nozzle is at its maximum height, the spout is at its maximum inclination and, on the horizontal plane, the projecting of its upper endis closer to the filling point than when the pump is at the lowest level.

The result of this is that if the centre of the connecting rodsupport arms, the centre of the pump and the filling point are alined, any rise in the level of the liquid metal tends to bring the pump closer to the filling point but at the same time, the horizontal distance between the top of the spout and the filling p'ointdecreases so that the lower end of the spout remains very substantially at the filling point.

The articulation between the upper portion of the spout and the casting nozzle of the burette can therefore be produced by means of a set of two link arms whose length enables the play resulting from the linear movement of the casting nozzle and the rotating of the spout about the filling point to be compensated.

The invention is therefore characterised also in that the means keeping the base of the liquid metal discharge spout at a fixed point called the filling point" are constituted by a displacement in the parallel planes of the axis of the support arm of the connecting rods of conduction pump having a liquid spiral in which may be distinguished at l, the cylindrical body containing at its upper part, the windings (not shown). The pump whose axis takes up the position X is immersed in a ladle 2 containing the liquid metal. The arrangement according to the invention enables the pump to be kept permenently immersed up to the level 3 which is adjustable by means of the counter weight 12, above the liquid spiral which remains hence permanently fed with liquid metal.

The pump, immersed in the liquid metal, is kept balanced under the effect of the Archimedean thrust and of the connecting rods 4 and 5. These connecting rods forms a parallelogram. The lower connecting rod 4 is extended at the upper end by an arm 6 supporting various elements forming a counter-weight. A system of connecting rods, not shown, identical to the connecting rods 4 and 4, is connected to the opposite face of the pump.

The connecting rods 4 and 5 are connected to the pump by trunnions 6 and 7 arranged on a generating line of the cylindrical body of the pump. At the other end, these connecting rods 4 and 5 are connected to a vertical arm 8 through trunnions 9 and 10.

On the mobile arm 4' extending the connecting rod 4 and on the arm not shown connected to the opposite face, the ventilator 11 whose function is to cool the the pump, of the axis of the pump and of the spout, as

well as by a link rod connection between the casting nozzle and the upper part of the spout.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows diagrammatically the arrangement which is the object of the invention, in the case of a windings contained in the cylindrical body 1 is arranged permanently. An extra adjustable counterweight 12 is connected to the arm 4.

The vertical arm 8 ends at its base with a leg 13 connected to the edge of the ladle by any known easily dismantled means. On this leg, there is a supply connection 14 connected to the ventilator 11 by a cable 15 running along the arm 4. A supply connection 16 also fixed to the leg 13 enables, moreover, the windings of the pump to the supplied by means of an electric duct 17 running along the upper connecting rod 5.

The pumped liquid metal rises along the inclined tube 20 ending in a casting nozzle 21. A link arm 22 connected to the casting nozzle 21 by trunnions 24 supports a spout 25. The spout 25 is also connected to the casting nozzle 21 by a second link arm, not shown, arranged symmetrically to the link arm 22 in relation to the plane of the FIGURE.

The liquid metal discharged by the pump flows along the spout 25 up to the filling point 26 where the opening of the receptacle (mould, crucible, etc to be filled with the metal contained in the ladle 2 is placed.

When the ladle 2 is full of metal, the pump and its arrangement take up the position shown in the FIGURE in a dotted line; the axis of the pump is then X.

During the operation of the pump, the level of the liquid metal goes down in the ladle 2. By means of the system of connecting rods 4 and 5, the pump undergoes a linear movement which keeps the pump in a vertical position; but this displacement comprises a horizontal component which tends to bring it closer to the arm 8, since the connecting rods 4 and 5 become inclined in relation to a horizontal plane. The result of this is that the horizontal distance between the casting nozzle 21 and the filling point 26 increases. This increase of the horizontal distance is compensated by the fact that the spout, following the vertical movement of the casting nozzle, becomes less inclined and compensates the horizontal component of the movement of the casting nozzle. The axis of the pump is displaced from X towards X.

The filling point remains fixed, the difference between the two displacements described above is slight and it is taken up completely by means of the set of link arms 22.

In conclusion the pump assembly and its arrangement constitute a block which man easily be transported an implanted on a ladle filled with liquid metal.

Although the device which has just been described may appear to afforded the greatest advantage in the arranging of an immersed electromagnetic pump, it will be understood that this arrangement may undergo various modifications consisting in replacing the means described above by other means which fultill the same technical function without going beyond the scope of the invention,

We claim:

1. In an arrangement wherein an electromagnetic cylindrical pump is immersed in a ladle of liquid metal and provides a discharge independent of the variations in the level of liquid metal, the improvement comprising: adjustable means for keeping the depth of immersion of the cylindrical pump constant and for simultaneously keeping the pump axis in a vertical position, said adjustable means comprising two sets of connecting rods 4 and 5 of the same length, each set forming an articulated parallelogram, trunnions 6 and 7 fixing two apices of the two parallelograms on a generating line of the cylindrical body of the pump, trunnions 9 and 10 fixing the other two apices respectively of said parallelogram to the liquid metal ladle and wherein one of the connecting rods of each set being extended towards the outside of the ladle by an arm 4 bearing an adjustable counterweight to enable the depth of immersion to be varied.

2. The arrangement as recited in claim 1, wherein the arms 4' support a ventilator 11 for said pump.

3. The arrangement as claimed in claim 1, further comprising a vertical arm 8 fixedly supporting said two trunnions 9 and 10 coupled to supporting rods 4 and 5, said vertical arm including a leg 13 at its base and dismantling means connecting said leg to the edge of the ladle 2.

4. The arrangement as claimed in claim 1, wherein a metal discharge spout 25 operatively coupled to said pump and means for insuring a fixed position with a base of the metal discharge spout regardless of variations in the level of liquid metal, said pump including an inclined tube extending upwardly within said ladle and terminating in a casting nozzle 21, and wherein said insuring means comprises link arms 22 arranged symmetrically on either side of the spout and pivotably connecting said casting nozzle 21 to the inboard end of said metal discharge spout 25. 

1. In an arrangement wherein an electromagnetic cylindrical pump is immersed in a ladle of liquid metal and provides a discharge independent of the variations in the level of liquid metal, the improvement comprising: adjustable means for keeping the depth of immersion of the cylindrical pump constant and for simultaneously keeping the pump axis in a vertical position, said adjustable means comprising two sets of connecting rods 4 and 5 of the same length, each set forming an articulated parallelogram, trunnions 6 and 7 fixing two apices of the two parallelograms on a generating line of the cylindrical body of the pump, trunnions 9 and 10 fixing the other two apices respectively of said parallelogram to the liquid metal ladle and wherein one of the connecting rods of each set being extended towards the outside of the ladle by an arm 4'' bearing an adjustable counterweight to enable the depth of immersion to be varied.
 2. The arrangement as recited in claim 1, wherein the arms 4'' support a ventilator 11 for said pump.
 3. The arrangement as claimed in claim 1, further comprising a vertical arm 8 fixedly supporting said two trunnions 9 and 10 coupled to supporting rods 4 and 5, said vertical arm including a leg 13 at its base and dismantling means connecting said leg to the edge of the ladle
 2. 4. The arrangement as claimed in claim 1, wherein a metal discharge spout 25 operatively coupled to said pump and means for insuring a fixed position with a base of the metal discharge spout regardless of variations in the level of liquid metal, said pump including an inclined tube extending upwardly within said ladle and terminating in a casting nozzle 21, and wherein said insuring means comprises link arms 22 arranged symmetrically on either side of the spout and pivotably connecting said casting nozzle 21 to the inboard end of said metal discharge spout
 25. 